STUN test issue - seems like there exist no STUN server anywhere that complies with this standard

[ravenrani]

Even the previously given server, now don't work.
Here is an example to verbose run -

I am particularly interested in 2 points -
[a] Is there any configuration that answers the 2nd test, of change port + change ip ? It seems like there is no configuration in which this doesn't return NULL.
[b] Is there any STUN server out there, that is compliant with the standard ? Or is there a need for a change in the code.
Why is the answer for the 2nd Test1 invalid ?

go-stun.exe -v 3 -s "stun.qwq.pink:3478"
2025/01/16 08:52:25 Do Test1
2025/01/16 08:52:25 Send To: 221.10.101.100:3478
2025/01/16 08:52:25
00000000 00 01 00 18 21 12 a4 42 0b 47 a3 0d 59 94 ac 5c |....!..B.G..Y..|
00000010 d9 bf 4b a0 80 22 00 0c 53 74 75 6e 43 6c 69 65 |..K.."..StunClie|
00000020 6e 74 00 00 80 28 00 04 61 92 7d 65 |nt...(..a.}e|
2025/01/16 08:52:28
00000000 01 01 00 54 21 12 a4 42 0b 47 a3 0d 59 94 ac 5c |...T!..B.G..Y..|
00000010 d9 bf 4b a0 00 20 00 08 00 01 2c 89 6c 9b ee d7 |..K.. ....,.l...|
00000020 00 01 00 08 00 01 0d 9b 4d 89 4a 95 80 2b 00 08 |........M.J..+..|
00000030 00 01 0d 96 dd 0a 65 64 80 2c 00 08 00 01 0d 97 |......ed.,......|
00000040 dd 0a 65 67 80 22 00 18 43 6f 74 75 72 6e 2d 34 |..eg."..Coturn-4|
00000050 2e 35 2e 32 20 27 64 61 6e 20 45 69 64 65 72 27 |.5.2 'dan Eider'|
00000060 80 28 00 04 2f cb 54 88 |.(../.T.|
2025/01/16 08:52:28 Received: {packet nil: false, local: %%%, remote: 221.10.101.100:3478, changed: , other: 221.10.101.103:3479, identical: false}
2025/01/16 08:52:28 Do Test2
2025/01/16 08:52:28 Send To: 221.10.101.100:3478
2025/01/16 08:52:28
00000000 00 01 00 20 21 12 a4 42 c2 4c f9 52 fa 02 f7 8c |... !..B.L.R....|
00000010 46 ad 6d 8f 80 22 00 0c 53 74 75 6e 43 6c 69 65 |F.m.."..StunClie|
00000020 6e 74 00 00 00 03 00 04 00 00 00 06 80 28 00 04 |nt...........(..|
00000030 e3 de 8a a2 |....|
2025/01/16 08:52:37 Received: Nil
2025/01/16 08:52:37 Do Test1
2025/01/16 08:52:37 Send To: 221.10.101.103:3479
2025/01/16 08:52:37
00000000 00 01 00 18 21 12 a4 42 85 f5 12 2f c4 60 b2 68 |....!..B.../.`.h|
00000010 05 2d de 35 80 22 00 0c 53 74 75 6e 43 6c 69 65 |.-.5."..StunClie|
00000020 6e 74 00 00 80 28 00 04 a6 7d dd 7d |nt...(...}.}|
2025/01/16 08:52:47 Received: Nil
NAT Type: Unexpected response from the STUN server
External IP Family: 1
External IP: &&&&&
External Port: 3483

[xlch88]

If you are not in mainland China, do not use this server

[xlch88]

https://gist.github.com/zziuni/3741933

[ravenrani]

None of the above list of STUN servers produce different result.
If all servers are producing the same results for the third test, after the failure with the 2nd,or actually the fact that nothing is returning. Then why does this test is failing always with unexpected response from STUN server ?
Moreover, it seems that there is not situation in which the second test returns with something else than null.

[xlch88]

2025/01/16 08:52:28 Received: {packet nil: false, local: %%%, remote: 221.10.101.100:3478, changed: , other: 221.10.101.103:3479, identical: false}

Are you sure the value of , changed: , in this line is an empty string? It should be , changed: <nil>,.

Would your outbound ip be varying during the test?

May you provide the full output without masking any ip?

[ravenrani]

I can do it, but it doesn't have anything to do with the IP.
The response for the 3rd test cannot be analyzed, and you got the full hex-dump of it.
Does it work for you ?
It used to work in the past, now it doesn't work anymore.
about the value of changed, this is the tool being executed with command line parameters, I haven't touched the code.